nav{
    text-align: center;
    
}
nav a{
    display: inline-block;
    color: blue;
    width: 200px;
    height: 50px;
    font-size: 25px;
    line-height: 50px;
    text-align: center;
    text-decoration: none;
    border: 0px;
    background-color:rgba(0, 0, 0, 0.4);
}
nav a:hover{
    color: white;
    background-color: rgba(0, 0, 0, 0.9);
}
nav a:first-child{
    color: white;
    background-color: rgba(0, 0, 0, 0.9);
}
p{
    font-size: 20px;
    text-indent: 40px;
}
.rb{
    border: 3px;
    width: 400px;
    height: 100px;

}
